Mechanism for adjusting the stroke of a reciprocating or oscillating member, such as a die plunger in an extrusion or molding press



May 8,-1945.

' A; RUSSELL EI'AL 2,375,693

G QR-OSCILLATING MECHANISM FOR ADJUSTING THE STROKE OF RECIPROCATINPLUNGERS IN KEXTRUSION. 0R MOLDING, PRESSES MEMBERS, SUCH AS DIE 3Sheets-Sheet 1 Filed Feb. ,24, 1944 y 1945- A. RUSSELL ETAL 2,375,

STROKE OF RECIPRQCATING GR 050 MECHANISM FOR ADJUSTING THE MEMBERS, SUCHAS DIE PLUNGERS IN EXTRUSION OR MOLDING PRESSES;

Filed Feb. 24, 1944 May 8, 1945.

MECHANISM FOR ADJUSTING THE MEMBERS, SUCH AS DIE PLUNGERS IN EXTRUSIONFiled Feb. 24, 1944 3 Sheets-Shet 3 Patented May 8, 1945 UN'TEDSTATESPATENT OFFICE MECHANISM FOR ADJUSTING THE STROKE OF A REC'IPROCAIJNG. ROSCILLATING MEMBER-SUCH As A mE PLUNGER IN AN EXTRUSION on. MOLDING Pnss 2 Alexander Russell, Matthew Parker, and Richard Anson Harris, Leeds,England, assignors to The ForgroveMachinery Gompany Limited, Leeds, v

England Application February 24, 1944, Serial No. 523,686

"In GreatBritain January 25, 1943 5 Claims. 01. 31-8) v The object ofthe invention is to provide an improved mechanism for "adjustingthestroke a reciprocating or oscillating member, such that theadjustment can be" performed while the member is in motion, and suchthat one end position of the stroke of the member is unaffected bytheadjustment, the other end position only being altered.

An adjustingmechanism of this character is, l l

for example, desirable in aplastic extruding machine, in which a "dieplunger reciprocates, in a a die chamber of which it formsthe bottomwhen in its lower position, the top of the chamberbeing covered by ahorizontally slidable plate during the time while the .material is beingextruded into the chamber through one of itssides. When extrusion iscompleted, the top plate is slid back to allow the plunger to lift theextruded b1ock out of the chamber, and afterwards returns to push theblock 01f the plunger. It is consequentwiththe under surface ofthe topplate, .so that when the latter moves .forward to close the chamberagainit W111 push the block of material ly important thatthe top of thedie plunger, h

when in its up position,should be exactly level.

off the die plunger cleanly, leaving a minimum of material sticking tothe plunger.

.When this dual purpose forwardmovementof the top plate is completed thedie plungerflde scends, ready for the nextextrusion. Regula tionof theamount of material contained in the extruded blocks has to be effectedby altering the volume of the extrusionchamber. 'I'heinvention enablesthis to'bedonewhilst the ma chine is running if necessary-by adjustingthe stroke of the die plunger, and as the top. position of the plungermust never change the whole of the variation takes place at the lowerposition.

The invention provides the combination with an adjustable-strokereciprocating or oscillating member, of mechanismoperable to adjust itsstroke while said; member is .in motion, which mechanism comprises afixedestroke actuating member, a normally stationary stroke-adjustingmember, ha linkage connecting the; actuating member and thestroke-adjusting membenpa will be unaffected by the adjustment.

vary the efi'ect ive stroke of the drivingconnection; i

As for all positions or adjustment or the stroke-adjusting member, thedriving member ,invariably comes to rest at afixedpoint at one end ofits to-and-frQ movement, one end position of the strokelof theadjustable stroke member By displacing the other end position of thepath of movement of the driving member, however, operation of thestroke-adjusting member will, by the consequent variation in theeffective stroke of the driving connection, alter the other end positionof the stroke'of the adjustable-stroke member. y l A A preferred form ofstroke-adjusting mechanism according to the invention comprises, incombinationwith the member of which the stroke'is to be adjusted, and afixed-stroke oscillatin actuating lever for communicating reciprocatingoroscillatory motion to .said member, ahadjustable lever pivoted on afixed centre, an operating pin coupled to said memben a first linkpivotally connected at its opposite "endsto the 1 positions. 3

With this arrangement the adjustable lever remains fixed, except when anadjustment is made, and the operating pin describes a circular are,

under the control of the first link, about the point of attachment ofthe'second link to the adjustablelever as centre, one end of thiscircular are being located at the point at which it meets theprojectionof the fixed centre; when t the adjustable lever is moved about thefixed driving member is. g., a pin) driven by said link-y age to executeto-and-fro movementfroma fixed 1 datum point, :and a'driving connectionbetween the driving member and the adjustable-stroke member, operationof the stroke-adjusting memberj serving to effect angular adjushnent ofthe path or movement of the drivingmember in relation t'o its fixed;-dewm" point, and thereby-to centre for adjustment purposes,the centreof oscillation of theoperating pin isof coursev displaced and the arc inwhich it travels moves bodily to a correspomiing extent about the fixedcentre. 'The extreme position of the operating pin at one; end of thearc remains coincident withthe fixed centre, but its position at theother endof the arc is of ooursevariedasa result of member tobeadjusted. l l .1

such adjustment, s0 varying thestroke of the "One specifio applicationof the invention, as

applied to the adjustment of th'e stroke of the die plunger of a machinefor wrapping plastic material, such as margarine, butter or the like,-will now be described in greater detail, by way of example, withreference to the accompanying drawings, in which-- Fig. 1 is a sideelevation partly in section of the die chamber, charging mechanismtherefor,

die-plunger and associated operating gear,

Fig. 2 is an enlarged side elevation of part of the mechanism foradjusting the stroke of the die plunger,

Fig. 3 is a plan view of the stroke-adjustina mechanism,

- Fig. 4 is a plan view of the upper part of the die chamber and itsmovable top cover,

box I2 located to one side of a rectangular section die chamber l3. Inthe die-chamber is a reciprocating die plunger 40, which constitutes thebottom of the chamber. The chamber is charged with margarine through thelateral opening I4 when the die plunger is in its bottom position shownin Fig. 1. The top of the 'diechamber is closed during extrusion, by asliding top cover plate l5, which moves in guides in fixed brackets l6,l1 (Figs. 4 and 5) and is operated by a rod l8 linked to a bellcrank-l9, which is periodically rocked to-and-fro about a fixed shaft 20by a cam 2| on the cam shaft'43 (Fig. 3). A reciprocating knife 22controls communication between the extrusion box [2 and the die chamberI3, the knife being operated by a cam 23 through the agency of a lever24 pivoted on a fixed shaft 42 (Fig. 3). During extrusion vided foraltering its bottom position, and so the volume of margarine extruded ateach stroke from the die chamber.

The wrapping machine is required to operate continuously all day, and isnot stopped when a fresh batch of margarine is put in. As the materialvaries, mainly due to differences of tem perature, and tendsto feedirregularly on this account, it is essential to be able to adjust thequantity of material extruded per cycle while the machine is running,This is achieved by varying the bottom datum point of the stroke of theplunger as will now be described.

the knife is in the down position, permitting, of

extrusion of' the margarine from the extrusion box into the die chamber.After the feed worms lll have ceased to rotate, the knife 22 moves up toclose the extrusion orifice, the displacement of margarine caused bythis upward movement of the knife ensuring that the die chamber iscompletely filled. The knife, when in the up position, cuts off the diechamber from residual pressure in the extrusion box. When the materialis soft this residual pressure might, but for the presenceof the knife,cause some of the material to ooze out of the top of the die chamber assoon as the top plate l5 begins to uncover the die chamber. Holes may,if desired, be provided in the wall 25 of the die box opposite theextrusionbox, to permit of egress of air and surplus margarine from thedie box on ascent of the knife. These holes are, however, not essential.

The top cover plate [5 moves to open the top of the die chamber whenextrusion has been completed, and this is the state of affairs shown inFig. 1. Immediately afterwards the plunger 40 rises to its top position,in which its upper surface. is level with the undersurface of the topcover plate [5. The latter then slides to the left (Fig. 1), whereuponan upstanding flange 25 on the top cover plate pushes the extruded blockof margarine off the die plunger 40 and on to a lifting plunger (notshown). I

It will be understood that thetop position of the die plunger 40'mustunder all conditions remain invariable. Means are, however, pro:

The plunger movement is derived from an actuating lever 46 which'isoscillated about the fixed shaft 42 by a cam 44 on the cam shaft 43. Tothis actuating lever 46 is pivoted at 50 a first link 41 pivoted at itsother end to an operating pin 49, which in turn is pivoted to a link end45 connectedto the plunger 40. This link end 45 thus constitutes adriving connection between the pin 49 and the plunger 40, theefiectivestroke of which is variable as described below.- The mechanismincludes an adjustable lever 51 pivoted at one end on a fixed pin 58 andpinned at its other end to a nut carried on a screwed adjusting rod 6|fitted with a hand-wheel 35 which is turned when it is desired todisplace the adjustable lever 51 about the fixed centre constituted bythe centre of the pin 58. Mounted on the rod 6| (see Fig. 1), betweenthe hand wheel 35 anda collar 10 pinned to the rod, is a bearing sleeve1| carrying a projecting pin 12 which is .journalled in a fixed framemember of the machine, so permitting the rod to swivel relatively to themachine frame (see Figs. 6 and 7) as the lever 51 swings about the pin58 to adjust the stroke of the plunger.

On a boss 4| on the adjustable lever is a pin 56 located at radius Rfrom the fixed centre. A link 54 of radius R is pivoted at its oppositeends to this pin 56 and to the operating pin 49. The mechanism thereforconsists of a closed or stable system of links, viz., the actuatinglever 46, the adjustable lever 51, the firstlink 41 and the second link54; and the movement communicated to the actuating lever 46 by the cam44 is such that in one of its two extreme positions the actuating lever46 brings the operating pin 49 into alignment with the fixed centre, asshown in full lines in Figs. 6 and 7. In each of these figures the partsare shown in chain-dottedlines in the position they occupy in theother'extreme position. Adjustment of the screwed rod6l will not varythis condition of alignment of the opcrating .pin with the fixed centrebut only the position to which the operating pin 49 is moved at theother end of its arcuate path about the pin 56 attaching the second link54 to the adjustable lever 51. The required adjustment of the bottomdatum point of the plunger stroke machine is running. 1

It will be appreciated, from a consideration of Figs. 6 and 7, that theoperating pin 49 always executes a to-and-fro movement in an arcuatepath one end of which is a fixed datum point constituted by the fixedcentre'of the-pin 58. The arcuate paths for two different positions ofadjustment of the lever 51 are shown in dot and dash lines in Figs. 6and 7. In Fig. 7 the arc in chain-dotted lines is that corresponding tothe condition of Fig. 6 and it will readily be seen that adjustment ofthe lever 51 causes the arcuate path of the pin 49 to move angularlyabout the fixed datum point. The efiective stroke of the driving link 45is represented by a in Fig. 6 and by b in Fig. '7. It is clearly less inFig. 7, so that in this case the stroke of the plunger 40 will beshorter (i. e., have a higher bottom datum point) than in Fig. 6.

The actuating lever 46 has an extension 30 which, when said lever is inthe extreme position (see Figs. 1 and 2) corresponding to the bottomposition of the plunger, abuts against a fixed stop 3| and so relievethe cam 44 from the forces developed in the die chamber by the extrusionoperation.

What we claim as our invention and desire to secure by Letters Patentis:

l. The combination with an adjustable-stroke driven member, and afixed-stroke actuating member for imparting motion to said drivenmember, of mechanism for adjusting the stroke of said driven memberwhile said member is in motion, said mechanism comprising anormallystationary stroke-adjusting member, a linkage connecting the actuatingmember and the stroke adjusting member, a driving member driven by said.linkage to execute movement to and from a fixed terminal point, adriving connection between said driving member and the driven memher,and means operable by the stroke-adjusting member to efiectangularadjustment of the path of movement of the driving member about saidfixed terminal point and thereby to vary the effective stroke of thedriving connection.

2. The combination with an adjustable-stroke reciprocating drivenmember, and a fixed-stroke actuating member for imparting motion to saiddriven member, of mechanism for adjusting the stroke of said drivenmember while said member is in motion, said mechanism comprising anormally stationary stroke-adjusting member, a

linkage connecting the actuating member andthe stroke-adjusting member,a driving pin driven by said linkage to execute movement to and from afixed terminal point, a driving connection between said driving pin andthe driven member, and means operable by the stroke-adjusting member toeffect angular adjustment of the path of movement of the driving pinabout said fixed terminal point and thereby to vary the efiective strokeof the driving connection.

3. The combination with an adjustable-strokethe operating pin and thedriven member, a first link pivotally connected at its opposite ends tothe operating pin and to the actuating lever, and a second linkpivotally connected at its opposite ends to the operating pin and to theadjustable lever, the length of said second link being equal to thedistance between the fixed centre and the point of pivotal connection ofthe second link to the adjustable lever, and said links serving, in

*all positions of adjustment, to maintain the operating pin inoscillation in an arcuate path one terminal whereof is in alignment withthe fixed V centre.

4. In a machine forextruding plastic material in shaped blocks, thecombination with an adjustable stroke reciprocating driven die plunger,and. a fixed stroke actuating member imparting motion to said drivenmember, of mechanism for adjusting the stroke of said die plunger whilethe plunger is in motion, said mechanism comprising a normallystationary stroke adjusting member, a linkage connecting the actuatingmember and the stroke adjusting member, a driving pin driven by saidlinkage to execute movement to and from afixed terminal point, a drivingconnection between said driving pin and the plunger, and means operableby the stroke adjusting member to efi'ect angular adjustment of the pathof movement of the driving pin about said-fixed terminal point, therebyto vary the effective stroke of the driving connection.

5. In a machine for wrapping plastic material,

the combination with a die chamber, of means for charging the diechamber with plastic material, a reciprocating variable stroke dieplunger constituting the bottom of the die chamber and operating todischarge shaped blocks of the plastic material from the top of saidchamber, a top cover for the die chamber, means for moving said cover toclose the top of the chamber during charging and to open the top of thechamber during the delivery stroke of the plunger, and means foradjusting the bottom limit of the stroke of the die plunger while thetop limit of its stroke remains unaltered comprising a fixed strokeactuating member for imparting motion to the die plunger, a normallystationary strokeadjusting member, a linkage connecting the actuatingmember and the stroke-adjusting memher, a driving pin driven by saidlinkage to execute movement to and from a fixed datum point, a drivingconnection between said driving pin and the die'plunger, and meansoperable by the stroke-adjusting member to effect angular ad-

